This invention relates to fiber-reinforced plastic articles and, more particularly, to a fiber-reinforced plastic connecting link or strut having a cylindrical body portion and first and second hollow cylindrical end portions having parallel axes which intersect the longitudinal axis of the cylindrical body portion.
Articles produced by this invention have particular utility as connecting rods in machinery where it is desirable to employ a lightweight connecting rod possessing high tensile, compressive, and torsional strengths. Such characteristics are particularly desirable for automotive and aircraft applications where strength-to-weight ratios are important design desiderata.
Various techniques have been proposed for fabricating fiber-reinforced plastic rodlike article which include variations of the basic pultrusion techniques developed by Francis and Meek in U.S. Pat. Nos. 2,602,766 and 2,684,318, respectively, and later perfected by Shobert in U.S. Pat. Nos. 2,852,425; 2,983,182; 3,007,497; and 3,033,729.
In Meek U.S. Pat. No. 2,684,318, there is disclosed and claimed a method for fabricating glass-reinforced plastic rods of solid cross section. In Francis U.S. Pat. No. 2,602,766, there is disclosed a method of fabricating hollow glass-reinforced plastic rods. These hollow rods are fabricated by first arranging a plurality of glass threads into a longitudinal bundle, inserting a mandrel into the central portion of the bundle so as to provide a core therefor, and, finally, braiding glass thread around the outer surface of the thread bundle. This braided bundle is thereafter immersed in resin which is cured to firmly bond the threads together in self-supporting form. The mandrel is thereupon removed, thereby providing a hollow center for the finished rod.
In Shobert U.S. Pat. No. 2,983,182, the patentee discloses a technique for fabricating tubing composed of two tubular laminations, the inner lamination comprising substantially straight, longitudinal threads distributed evenly circumferentially, and the outer lamination comprising helically wound threads. In U.S. Pat. No. 3,007,497 to Shobert, the patentee provides a technique for interlocking helical and longitudinal strands to ensure that the longitudinal strands will be evenly distributed about the circumference of the rod.
All of these techniques are directed to batch or continuous operations for producing fiber-reinforced plastic rods wherein the fibers are helically woven on a mandrel or longitudinally arranged with or without a supporting mandrel, and wherein the weaving or arranging progresses along a single axis. To applicant's knowledge, no attempt has been made to conduct weaving or filament laying operations on a winding form which includes a plurality of cylindrical portions having intersecting axes.